1. Field of the Invention
The present invention relates generally to a circuit-terminal connecting device, and more particularly to an improvement in a circuit-terminal connecting device which comprises first and second electrical connectors fixed respectively to first and second circuit boards including flexible printed circuit boards (FPCs) to be used for putting first and second groups of circuit-terminals provided respectively on the first and second circuit boards in mutual electrical connection under a condition wherein the first and second electrical connectors are coupled with each other so that the second circuit board is closely laid on top of the first circuit board.
2. Description of the Prior Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98
Various kinds of electric or electronic parts are built even in a relatively small-sized electronic apparatus such as a mobile phone or the like. A major part of those parts are dispersedly mounted on, for example, a couple of separate circuit boards to fulfill their respective functions. In the relatively small-sized electronic apparatus, having an eye to the couple of separate circuit boards on which the electric or electronic parts are mounted, it is likely that one of the separate circuit boards is required to be closely laid on top of the other of the separate circuit boards for reducing a space occupied thereby when the separate circuit boards are electrically connected with each other. Such electrical connection between the separate circuit boards wherein one is closely laid on top of the other is hereinafter referred to as electrical piled-up connection.
In general, when a plurality of groups of circuit-terminals provided respectively on a plurality of circuit boards are put in mutual electrical connection, a plurality of electrical connectors are respectively fixed to the circuit boards, and one of the electrical connectors is coupled with another of the electrical connectors so as to connect the circuit boards, on which the electrical connectors are respectively fixed, electrically with each other. In case of such an electrical piled-up connection as mentioned above, first and second electrical connectors are respectively fixed on the separate circuit boards to be coupled with each other. For example, the first electrical connector is formed into a receptacle type connector and the second electrical connector is formed into a plug type connector to be a mate electrical connector, so that the plug type connector is engaged with the receptacle type connector when the separate circuit boards are put in a condition of the electrical piled-up connection. The first and second connectors provided to be coupled with each other as described above are required to be maintained stably in a mutual coupling condition.
Under such a situation, there have been previously proposed several circuit-terminal connecting devices, each of which comprises first and second electrical connectors fixed respectively to first and second circuit boards and locking means for locking mechanically the first or second electrical connector to the second or first electrical connector when the first and second electrical connectors are coupled with each other for putting first circuit-terminals provided on the first circuit board and second circuit-terminals provided on the second circuit board in mutual electrical connection, as disclosed in, for example, the Japanese patent application published before examination under publication number 2005-267977 (hereinafter, referred to as published prior art document 1) and the Japanese patent application published before examination under publication number 2009-170250 (hereinafter, referred to as published prior art document 2).
A circuit-terminal connecting device disclosed in the published prior art document 1 comprises a first electrical connector (a plug connector 100) having a first housing (an insulator 11) and a manipulatable member (a pull-bar 10) mounted on the first housing to be rotatable and a second electrical connector (a receptacle connector 102) having a second housing (an insulator 21). The manipulatable member mounted on the first housing is made of metallic bar material to have an arm portion (10b) at each of both ends thereof and a rotating axis (10a) to form a top end of the arm portion. The rotating axis extends to pass through an outside wall portion of the first housing from the outside to the inside of the same so as to constitute a locking portion (a part of a locking mechanism) to the second electrical connector. A rib (7) is provided on an external surface of the outside wall portion of the first housing to project outwardly and a protrusion (1) is provided on an external surface of an inside wall portion of the second housing.
When the first and second electrical connectors are coupled with each other, the outside wall portion of the first housing of the first electrical connector is placed at the outside of the inside wall portion of the second housing of the second electrical connector so that the first housing is engaged with the second housing. On that occasion, the rotating axis of the manipulatable member provided on the first housing of the first electrical connector engages with the protrusion provided on the external surface of the inside wall portion of the second housing of the second electrical connector to put the first housing in mechanical lock to the second housing so that first and second electrical connectors are maintained in the mutual coupling condition.
After that, when the manipulatable member provided on the first housing of the first electrical connector is rotated, the arm portion of the manipulatable member is moved to get on the rib provided on the external surface of the outside wall portion of the first housing so that the manipulatable member is resiliently deformed to shift the rotating axis of the manipulatable member to the outside of the inside wall portion of the second housing of the second electrical connector and thereby the rotating axis of the manipulatable member disengages from the protrusion provided on the external surface of the inside wall portion of the second housing. Consequently, the first housing is released from the mechanical lock to the second housing by the locking portion including the rotating axis of the manipulatable member. After the rotating axis of the manipulatable member has disengaged from the protrusion provided on the external surface of the inside wall portion of the second housing, the manipulatable member is further rotated to be resiliently restored to the original state.
Then, a circuit-terminal connecting device disclosed in the published prior art document 2 comprises a first electrical connector (a receptacle connector 200) having a first housing (an insulator 202) and a metallic member (a shell 250) covering a major part of the first housing and a second electrical connector (a plug connector 300) having a second housing (an insulator 340) and a manipulatable member (a pull-bar 370) mounted on the second housing to be rotatable. The metallic member of the first electrical connector has a locking portion (252) on which an engaging hole (254) is formed. The manipulatable member mounted on the second housing is made of metallic bar material to have a main portion (372), a connecting portion (376) extending to be bent in a direction crossing the main portion from each of end portions of the main portion opposite to each other, and an engaging portion (374) extending to be bent further in a direction along the main portion from each of the connecting portions. The second housing of the second electrical connector has an outside wall portion, on an internal surface of which a cam portion (348) is provided. The engaging portion of the manipulatable member extends to pass through the outside wall portion of the second housing from the inside to the outside of the same so that a top end of the engaging portion projects to the outside of the outside wall portion of the second housing to constitute a locking end portion (375) to the first housing of the first electrical connector.
When the first and second electrical connectors are coupled with each other, the outside wall portion of the second housing of the second electrical connector is placed at the inside of the locking portion of the metallic member of the first electrical connector, on which the engaging hole is formed, so that the second housing is engaged with the first housing. On that occasion, the locking end portion at the top end of the engaging portion of the manipulatable member provided on the second housing of the second electrical connector engages with the engaging hole formed on the locking portion of the metallic member of the first electrical connector to put the second housing in mechanical lock to the first housing so that first and second electrical connectors are maintained in the mutual coupling condition.
After that, when the manipulatable member provided on the second housing of the second electrical connector is rotated, the connecting portion of the manipulatable member is moved under guidance with the cam provided on the internal surface of the outside wall portion of the second housing so that the manipulatable member is resiliently deformed to shift the locking portion at the top end of the engaging portion extending to be bent from the connecting portion of the manipulatable member to the inside of the outside wall portion of the second housing and thereby the locking end portion at the top end of the engaging portion of the manipulatable member disengages from the engaging hole formed on the locking portion of the metallic member of the first electrical connector. Consequently, the second housing is released from the mechanical lock to the first housing by the locking end portion at the top end of the engaging portion of the manipulatable member. After the locking end portion of the manipulatable member has disengaged from the engaging hole formed on the locking portion of the metallic member of the first electrical connector, the manipulatable member is further rotated to be resiliently restored to the original state.
In the previously proposed circuit-terminal connecting devices, each of which comprises first and second electrical connectors fixed respectively to first and second circuit boards and locking means for locking mechanically the first or second electrical connector to the second or first electrical connector when the first and second electrical connectors are coupled with each other for putting first circuit-terminals provided on the first circuit board and second circuit-terminals provided on the second circuit board in mutual electrical connection, as described above, there are the following defects or disadvantages.
In the case of the circuit-terminal connecting device disclosed in the published prior art document 1, the rotating axis of the manipulatable member made of metallic bar material to be provided on the first housing of the first electrical connector engages with the protrusion provided on the second housing of the second electrical connector to put the first housing in mechanical lock to the second housing under a condition wherein the manipulatable member is not resiliently deformed when the first and second electrical connectors are coupled with each other and then the rotating axis of the manipulatable member disengages from the protrusion provided on the second housing to release the first housing from the mechanical lock to the second housing under a condition wherein the manipulatable member is resiliently deformed. Accordingly, under a condition wherein a locked state in which the first housing is put in the mechanical lock to the second housing and an unlocked state in which the first housing is released from the mechanical lock to the second housing are taken repeatedly, the rotating axis of the manipulatable member engages with the protrusion provided on the second housing to put the first housing in the mechanical lock to the second housing under a condition wherein the manipulatable member is caused to restore not to be resiliently deformed after being once deformed resiliently.
Therefore, it is feared that the arm portion of the manipulatable member is undesirably subjected to plastic deformation so as not to restore appropriately to the original state when the manipulatable member is caused to restore not to be resiliently deformed after being once deformed resiliently. In the case where such a plastic deformation as mentioned above is brought on the arm portion of the manipulatable member, the rotating axis of the manipulatable member is shifted in its position by the plastic deformation of the arm portion of the manipulatable member so as not to engage appropriately with the protrusion provided on the second housing and thereby the first housing is put in unsure or unstable mechanical lock to the second housing.
Further, in the circuit-terminal connecting device disclosed in the published prior art document 1, the rotating axis of the manipulatable member is supported by the outside wall portion of the first housing after having passed through the same from the outside to the inside thereof to engage with the protrusion provided on the second housing. That is, the rotating axis of the manipulatable member is not supported by any metallic member having relatively large stiffness but supported by the first housing made of insulating material inferior in stiffness for locking the first housing to the second housing. Therefore, especially under a situation wherein a thickness of each of the first and second housings is reduces for miniaturization and reduction in weight of the first and second electrical connectors, it is feared that the rotating axis of the manipulatable member is unsurely or unstably supported by the outside wall portion of the first housing so as not to engage surely and reliably with the protrusion provided on the second housing.
Then, in the case of the circuit-terminal connecting device disclosed in the published prior art document 2, the locking end portion at the top end of the engaging portion of the manipulatable member made of metallic bar material to be provided on the second housing of the second electrical connector engages with the engaging hole formed on the locking portion of the metallic member of the first electrical connector to put the second housing in mechanical lock to the first housing under a condition wherein the manipulatable member is not resiliently deformed when the first and second electrical connectors are coupled with each other and then the locking end portion of the manipulatable member disengages from the engaging hole formed on the locking portion of the metallic member of the first electrical connector to release the second housing from the mechanical lock to the first housing under a condition wherein the manipulatable member is resiliently deformed. Accordingly, under a condition wherein a locked state in which the second housing is put in the mechanical lock to the first housing and an unlocked state in which the second housing is released from the mechanical lock to the first housing are taken repeatedly, the locking end portion of the manipulatable member engages with the engaging hole formed on the locking portion of the metallic member of the first electrical connector to put the second housing in the mechanical lock to the first housing under a condition wherein the manipulatable member is caused to restore not to be resiliently deformed after being once deformed resiliently.
Therefore, it is feared that the engaging portion of the manipulatable member is undesirably subjected to plastic deformation so as not to restore appropriately to the original state when the manipulatable member is caused to restore not to be resiliently deformed after being once deformed resiliently. In the case where such a plastic deformation as mentioned above is brought on the engaging portion of the manipulatable member, the locking end portion of the manipulatable member is shifted in its position by the plastic deformation of the engaging portion of the manipulatable member so as not to engage appropriately with the engaging hole formed on the locking portion of the metallic member of the first electrical connector and thereby the second housing is put in unsure or unstable mechanical lock to the first housing.
Further, in the circuit-terminal connecting device disclosed in the published prior art document 2, the engaging portion of the manipulatable member is supported by the outside wall portion of the second housing, on the internal surface of which the cam portion is provided, after having passed through the same from the inside to the outside thereof so as to cause the locking end portion at the top end of the engaging portion to engage with the engaging hole formed on the locking portion of the metallic member of the first electrical connector. That is, the engaging portion of the manipulatable member having the locking end portion at its top end is not supported by any metallic member having relatively large stiffness but supported by the second housing made of insulating material inferior in stiffness for locking the second housing to the first housing. Therefore, especially under a situation wherein a thickness of each of the first and second housings is reduces for miniaturization and reduction in weight of the first and second electrical connectors, it is feared that the engaging portion of the manipulatable member is unsurely or unstably supported by the outside wall portion of the second housing so that the locking end portion at the top end of the engaging portion is not able to engage surely and reliably with the engaging hole formed on the locking portion of the metallic member of the first electrical connector.